1. Field of the Invention
The present invention relates to a camera and a strobe device, and more particularly, to a camera and a strobe device which can vary a color temperature of an emitted light color of strobe light.
2. Description of the Related Art
A camera provided with an auto bracketing shooting function has been widely known in which multiple photos are continuously and automatically shot only with one release operation while the exposure value is varied stepwise, with respect to a determined exposure value of the camera, that is, shutter speed and an aperture value.
Japanese Patent Application Laid-Open No. 5-196985 describes a technique capable of quickly and accurately performing the auto bracketing shooting even if the auto bracketing shooting is performed by using a strobe device.
Moreover, among cameras such as digital still cameras, there is also a camera provided with a white balance bracketing shooting function in which a variable parameter for the bracketing shooting is white balance instead of the exposure value.
Japanese Patent Application Laid-Open No. 2001-333432 describes a technique of the white balance bracketing shooting function in which multiple photos can be continuously and automatically shot while the white balance is varied stepwise only with one release operation.
Moreover, a conventional strobe device of a camera uses a xenon tube as a light source. For example, if strobe shooting is performed in order to correct backlight under sunlight in the morning or the evening, since the xenon tube has spectral characteristics close to daylight colors, the photos may be in unnatural colors.
Japanese Patent Application Laid-Open No. 2002-116481 describes a technique in which a color temperature of an emitted light color can be manually or automatically varied by using light emitting elements of R, G and B, and for example, if the backlight under the sunlight in the morning or the evening is corrected, the backlight correction in accordance with a color temperature of the sunlight can be performed to eliminate unnaturalness due to a color temperature of strobe light at the time of the strobe shooting.
However, in the invention according to Japanese Patent Application Laid-Open No. 5-196985, although the images at an appropriate exposure can be obtained by using the strobe device, since a color temperature of a strobe light source is constant, for example, if the backlight under the sunlight in the morning or the evening is corrected, the photos may be in the unnatural colors.
Moreover, in the invention according to Japanese Patent Application Laid-Open No. 2001-333432, for example, if a strobe is used in order to correct the backlight under the sunlight in the morning or the evening, since the color temperature of the strobe light source and the color temperature of the sunlight are different, it is difficult to perform the shooting with good white balance for both a subject illuminated with the strobe light source and a background illuminated with the sunlight in the white balance bracketing shooting.
Moreover, in the invention according to Japanese Patent Application Laid-Open No. 2002-116481, if there is any error in measurement of a color temperature of a subject field, there is a problem that the color temperature of the strobe light which has been set based on a result of the measurement cannot match the color temperature of the subject field.
In the invention according to Japanese Patent Application Laid-Open No. 2002-116481, after the color temperature of the emitted light color has been manually or automatically set, it is necessary to convert the set color temperature into a ratio of light emission amounts of R, G and B. For this purpose, a method of having a correspondence table between the color temperature and the RGB ratio in an EEPROM or the like is conceivable.
However, even with the same color temperature difference, the colors significantly vary in an area of a low color temperature, while the colors insignificantly vary in an area of a high color temperature. Therefore, if RGB ratio data is held at regular intervals of the color temperature, there is a problem in which the color temperature cannot be finely set in the area of the low color temperature if the intervals of the color temperature are wide, and useless data increases in the area of the high color temperature if the intervals of the color temperature are narrow.